A flat-panel CRT display basically consists of an electron-emitting device and a light-emitting device. Electrons emitted by the electron-emitting device, commonly referred to as a cathode, strike the light-emitting device and cause it to emit light that produces an image on the viewing surface of the display.
FIG. 1 presents a side cross section of part of the active imaging region of a conventional flat-panel CRT display such as that described in U.S. Pat. No. 6,049,165. Electron-emitting device 10 of this conventional display is coupled to light-emitting device 12 through an outer wall (not visible here) to form sealed enclosure 14 maintained at a low internal pressure e.g., 10−6 torr. A spacer system is situated inside enclosure 14 for maintaining a relatively uniform separation between devices 10 and 12 and for preventing the external-to-internal pressure differential of approximately 1 atm. from the collapsing the display. The spacer system consists of generally parallel spacer walls 16, one of which is shown in FIG. 1.
FIG. 2 illustrates the layout of electron-emitting device 10 as seen along a plane extending laterally through sealed enclosure 14. Device 10 consists of backplate 20 and a group of layers/regions situated on the interior surface of backplate 20. The layers/regions include an array of equally spaced rows and equally spaced columns of electron-emissive regions 22. The layers/regions also include electron-focusing system 24 having openings 26 through which electron-emissive regions 22 are exposed to enclosure 14. Item 28 in FIG. 1 represents the trajectory of an electron which is emitted by one of regions 22 and which travels through overlying focus opening 26 to light-emitting device 12.
Light-emitting device 12 consists of transparent faceplate 30, an array of equally spaced rows and equally spaced columns of light-emissive regions 32, black matrix 34, and light-reflective anode layer 36 arranged as shown in FIG. 1. Each light-emissive region 32 is situated directly opposite a corresponding different one of electron-emissive regions 22. Upon being selectively struck by electrons emitted by regions 22, light-emissive regions 32 emit light to produce an image on the exterior surface of faceplate 30 at the front of the display.
As indicated in FIGS. 1 and 2, each spacer wall 16 contacts electron-focusing system 24 along a location above the space between a pair of consecutive rows of electron-emissive regions 22. Although spacer walls 16 maintain a relatively uniform spacing between devices 10 and 12, the presence of walls 16 restrict the dimensions of electron-emissive regions 22 in the direction of the columns of regions 22, i.e., in the direction perpendicular to walls 16. It would be desirable to configure a flat-panel CRT display in such a manner that the presence of spacer walls places less restriction on the lateral dimensions of electron-emissive regions in the direction perpendicular to the spacer walls.